1. Field of the Invention
The present invention relates in general to a novel rotational angle sensor which provides corresponding electrical signals in response to rotational angles detected by the sensor.
2. Description of the Prior Art
One prior art sensor of the type disclosed herein includes a movable body capabe of angular displacement on a rotary axis and a potentiometer having a slider linked to the movable body. In this sensor, the potentiometer provides an analog voltage output according to the amount of the angular displacement of the movable body. In this type of sensor, it is desirable that the potentiometer have a thin-film resistor which has a high wear resistance. It is also desirable for the potentiometer to provide a stable output voltage level in response to the positions to be assumed by the slider. It is further desirable that the linkage connecting the movable body with the slider should be operated with reliable stability without causing loose connections. Furthermore, the contact between the slider and the thin-film resistor should desirably take place with sufficient stability to permit the two contacting parts to resist any vibrations and shocks.
In the prior art sensor, however, the contact between the slider and thin-film resistor in the potentiometer is implemented by pressure, so that as any one or both of the two contacting elements wear with time or when vibrations or shocks occur, the potentiometer eventually provides incorrect or improper output voltages in response to the angular displacement of the movable body.